1. Field of the Invention:
The present invention relates to oil well logging apparatus, and more particularly to an oil well immersible instrument array which provides various measured indications such as the percentage of oil within the well fluid, the timperature of the fluid, the flow rate of the fluid and the pressure of the fluid at various stations in the well.
2. Description of the Prior Art:
Collection of crude petroleum very often entails economic considerations beyond the determination of mere presence of crude oil. Most often the economics of producing oil are complicated by overabundant presence of subterranean water flows which may enter a well bore at various depths. Since all the fluids are ordinarily pumped out of the well bore, an overabundant presence of water mixed with the oil inordinately increases pumping costs. Very often the percentage of water that has to be pumped in order to bring out, or produce, the oil is so high that oil production becomes uneconomical.
In most well bores, a casing is utilized which at various stations includes lateral perforations through which the fluids below ground enter the bore. In the past, various techniques have been developed by which selected perforations can be sealed off so that fluid flow only from selected subsurface strata is permitted to enter the bore. It thus became essential in the art to develop meansurement techniques to determine the relative percentages, or the relative proportions, of water at various bore stations and thereby determine which stations are to be sealed off. In order to achieve a comprehensive reading or measurement with respect to bore station, multiple parameters are required, such as the fluid composition, the flow rate of the fluid, the pressure head and temperature.
Most prior art devices directed at such measurement of the fluid composition within a well bore required extensive local instrumentation which resulted in large packages tending to restrict the flow and thereby introducing an extraneous source of error. In addition, such prior art instrumentation arrays were limited to only a few or a single measuring instrument for each insertion into the well bore. This resulted in an increase in cost of the measuring process and furthermore increased the inaccuracy of the measurement process since measurements were distributed with time, with the attendant loss of instantaneous cross-correlation.